Method for preparing conductive composite materials by deposition of a conductive polymer in an insulating porous substrate and solution for use in said preparation

Abstract

The invention relates to a method of preparing a conductive composite material, consisting of performing at least one cycle of deposition comprising the following steps: (a) putting an insulating porous substrate ( 1 ) in contact with a solution of a conductive polymer such as polyaniline in a volatile organic solvent such as trifluoroacetic acid, and (b) eliminating the organic solvent by evaporation, for forming a deposit of conductive polymer ( 5 ) in the pores ( 3 ) of the porous substrate.

What is claimed is:  
     
       1. Method for preparing an electrically conductive composite material, comprising an insulating porous substrate and a conductive polymer arranged in the pores of the insulating substrate, comprising performing at least one depositing cycle of the conductive polymer comprising the following steps: 
       (a) putting the porous substrate in contact with a solution of the conductive polymer in a volatile organic solvent, chemically inert with respect to the porous substrate, said organic solvent being chosen from the group consisting of acetic acid, halogenated derivatives of acetic acid and fluorinated alcohols: and  
       (b) eliminating the volatile organic solvent by evaporation to form a deposit of conductive polymer in the pores of the porous substrate.  
     
     
       2. Method according to  claim 1 , in which three successive depositing cycles are performed. 
     
     
       3. Method according to  claim 1 , in which the solution of the conductive polymer contains 1 to 10 g/l of conductive polymer. 
     
     
       4. Method according to  claim 1 , wherein the organic solvent is trifluoroacetic acid. 
     
     
       5. Method according to  claim 1 , in which the conductive polymer is a polyaniline. 
     
     
       6. Method according to  claim 5 , wherein the polyaniline is in the form of emerald base. 
     
     
       7. Method according to  claim 5 , wherein the solution of the conductive polymer is a solution of polyaniline and of a protonating agent in an amphiphilic volatile organic solvent. 
     
     
       8. Method according to  claim 7 , wherein the protonating agent is chosen among the aliphatic and/or aromatic monoesters and diesters of phosphoric acid, sulfonic acids, and phosphonic acids. 
     
     
       9. Method according to  claim 8 , in which the protonating agent is camphorsulfonic acid. 
     
     
       10. Method according to  claim 1 , wherein the porous substrate is a material chosen among insulating polymers, filter papers, glasses and ceramics. 
     
     
       11. Method according to  claim 1 , wherein the contacting of the porous substrate with the solution of the conductive polymer is performed by immersion of the substrate in the solution or by spraying the solution onto the substrate.